The United Kingdom has sent troops to Gatwick Airport after large drones forced all flights to be cancelled in an unprecedented attempt to cripple Christmas travel.
- A police hunt for the drone operators has so far been unsuccessful
- The airport will remain closed until 6:00am local time (5:00pm AEDT)
- Some 115,000 people were scheduled to pass through the airport today but flights are now shut down
As thousands of passengers waited at Britain's second-largest airport, police hunted unsuccessfully for the operators of the large drones which reappeared near the airfield every time the airport tried to reopen the runway.
Police said there was no indication the people using the drones, which first appeared on Wednesday night, had terrorism-linked motivations.
"We will be deploying the armed forces," Defence Minister Gavin Williamson told reporters. "We are there to assist and do everything we can."
Europe's air traffic control agency Eurocontrol said the airport would remain closed until 6:00am GMT (5:00pm AEDT) on Friday.
Drones were seen as recently as the last hour, a Gatwick spokesman said at about 10:00pm on Thursday (local time), more than 24 hours after their first sighting.
The airport said flights would remain shut down for the rest of the evening on a day when 115,000 people were scheduled to pass through, many en route to seasonal breaks.
Prime Minister Theresa May's spokesman condemned the standoff as "irresponsible and completely unacceptable".
Passenger Ani Kochiashvili was bound for Georgia, but instead spent six hours overnight sitting on a plane with her children.
"I'm very annoyed because I'm with two kids, a three-month-old and three-year-old," she said by phone, among thousands camped in the terminal.
"They require a lot of space and food and changing and all that, and the airport is crazy busy, so it's challenging."
Flights were halted on Wednesday evening after the two drones were spotted near the airfield, 50 kilometres south of London, triggering the biggest disruption at Gatwick since a volcanic ash cloud in 2010.
Standoff in the sky
Police said more than 20 units were hunting the operators but Gatwick's chief operating officer Chris Woodroofe said shooting drones was not an option.
"The police advice is that it would be dangerous to seek to shoot the drone down because of what may happen to the stray bullets," he told BBC radio.
Transport Minister Chris Grayling the disruption was clearly a deliberate act.
"This is a commercial-sized drone," he said.
"Every time Gatwick tries to reopen the runway, the drones reappear."
Richard Parker, head of air traffic management technology firm Altitude Angel, said the culprits were clearly well coordinated.
"It's sophisticated, not from a technology side, but it's organised," Mr Parker said.
"People have charged lots of batteries, and are deliberately trying to avoid being caught, probably by driving around to different locations."
Mr Grayling temporarily lifted night-flying restrictions at other airports to ease congestion caused by diverted aircraft, Sky News reported.
Drone expert Peter Lee of Portsmouth University said with the introduction of cheap, commercially-available drone technology, he and others had been anticipating this kind of disruption.
"You can achieve a high amount of disruption for a very, very low cost," he said.
"One of my concerns about today is that it may well encourage copycat incidents."
With a surge in public enthusiasm for drones, there has been an increase in near-collisions by unmanned aircraft and commercial jets in recent years.
The number of near misses between private drones and aircraft in Britain more than tripled between 2015 and 2017, with 92 incidents recorded last year, according to the UK Airprox Board regulator.
"These events obviously highlight a wider strategic challenge for aviation in this country which we need to address together with speed," Gatwick Airport chief executive Stewart Wingate said.
"It cannot be right that drones can close a vital part of our national infrastructure in this way.
"This is obviously a relatively new technology and we need to think through together the right solutions to make sure it cannot happen again."
It is illegal to fly drones within one kilometre of a British airport boundary. Breaches of the law can attract a five-year jail term.
'Complete mayhem' to continue
Even after Gatwick reopens, the backlog and disruption are expected to last for days.
Gatwick said it was working with its airlines, the biggest of which also include British Airways and Norwegian, on recovery plans.
Safety is its "foremost priority", it said.
Gatwick, which competes with Europe's busiest airport Heathrow, west of London, had previously said Sunday would be its busiest day of the festive period.
Passengers have taken to Twitter to share their stories about the delays.
One waiting at the airport said: "At Gatwick Airport, drone chaos, surprisingly good natured, but complete mayhem."